# cossacklabs/themis

Easy to use cryptographic framework for data protection: secure messaging with forward secrecy and secure data storage. Has unified APIs across 14 platforms.

Repository: https://github.com/cossacklabs/themis
Canonical: https://ross.abutalabs.com/products/themis
Homepage: https://www.cossacklabs.com/themis
Language: C
License: Apache-2.0
License Family: permissive
Topics: cryptography-library, cryptography, security, golang, ios, swift, objective-c, python, ruby, php, java, javascript, authentication, secure-messenger, secure-storage, encryption, symmetric-cryptography, asymmetric-cryptography, rust, owasp
Last push: 2026-04-24T14:01:56+00:00

## Health v2 (maintenance only)
Score: 76/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 79, release rhythm 57, longevity 100
- inputs: {"age_days": 4137, "days_push": 131, "days_rel": 131, "gap_med": 104, "n_releases_24m": 2}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 1973, forks 159 (observed 2026-08-28T04:06:01.123821+00:00)

## What it is
Themis is a cross-platform, high-level cryptographic library providing ready-made building blocks for secure data storage, encrypted messaging, session-based encryption with forward secrecy, and zero-knowledge authentication. It offers unified APIs across 14 platforms and languages including Swift, Java/Kotlin, Python, Go, Rust, and JavaScript/WASM, hiding cryptographic details to prevent developer mistakes.

## Use cases
- encrypt stored secrets like API keys, session tokens, and files
- add end-to-end encryption to a mobile chat app
- encrypt sensitive database fields at the application level
- build secure real-time sessions with forward secrecy for IoT device control
- authenticate users with zero-knowledge proofs without sending passwords
- exchange encrypted and signed messages between client and server
- use one consistent crypto API across iOS, Android, and backend

## When to choose
- you need usable, hard-to-misuse cryptography across multiple platforms with consistent behavior
- you want high-level primitives (storage encryption, secure messaging, sessions) instead of assembling raw crypto algorithms
- you're building a mobile or multi-platform app that OWASP-recommended, audited crypto
- you need forward secrecy or zero-knowledge authentication without implementing protocols yourself

## When to avoid
- you need low-level control over cryptographic primitives or custom protocol construction
- you need FIPS-validated or formally certified cryptography for compliance regimes
- your platform or language is outside the 14 supported ones (e.g., experimental Windows support only)
- you only need TLS for transport security - standard libraries suffice

## Facets
- artifact type: library
- maturity: stable
- function: cryptography, security, auth, sdk
- domain: security, privacy, mobile-development, web-development, developer-tools
- platform: windows, cross-platform, python, go, rust, jvm, php, ruby, cpp, wasm
- tags: secure-messaging, secure-storage, forward-secrecy, zero-knowledge-proof, end-to-end-encryption, field-level-encryption, owasp, multi-platform, high-level-crypto, secure-cell, secure-session, secure-message, secure-comparator, ios, android, macos, linux, nodejs, mobile, desktop, web-server

## Member repositories
- cossacklabs/themis (main) score 76

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:01.123821+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T03:04:57.992203+00:00, confidence not recorded.
  - readme: https://github.com/cossacklabs/themis (fetched 2026-08-28T04:06:01.123821+00:00, sha e39f47c42542)
  - homepage: https://www.cossacklabs.com/themis (fetched 2026-08-29T10:44:37.384536+00:00, sha 74b4c48f7a6d)
  - site_page: https://docs.cossacklabs.com/ (fetched 2026-08-29T10:44:37.394401+00:00, sha 62106cd6d23a)
  - site_page: https://www.cossacklabs.com/about (fetched 2026-08-29T10:44:37.396314+00:00, sha 8e5ff75638da)
  - site_page: https://www.cossacklabs.com/documentation (fetched 2026-08-29T10:44:37.400249+00:00, sha 975dcf666f67)
  - site_page: https://docs.cossacklabs.com/themis/getting-started (fetched 2026-08-29T10:44:37.401916+00:00, sha 6d8ca09ed7ae)
  - site_page: https://docs.cossacklabs.com/products/themis (fetched 2026-08-29T10:44:37.403564+00:00, sha 0ee955c3f54a)
  - site_page: https://docs.cossacklabs.com/themis/community (fetched 2026-08-29T10:44:37.405334+00:00, sha 256def454990)
  - site_page: https://www.cossacklabs.com/news (fetched 2026-08-29T10:44:37.398352+00:00, sha 3901be7c4841)
  - site_page: https://www.cossacklabs.com/faq (fetched 2026-08-29T10:44:37.407035+00:00, sha 3f8021f08a23)
- Data as of 2026-08-30T08:39:29.467469+00:00.